        <!DOCTYPE html>
<html lang="en">
    <head>
    <meta charset="UTF-8">
    <title>flappy_bird</title>
    <style>
		body{background-color: #2A2A2A}
canvas {
	display: block;
	border: 1px solid #313131;
	margin-left: auto;
	margin-right: auto;
	margin-top: 50px;
}
img {
	display: none;
}
</style>
    </head>
    <body>
<canvas id="cvs" width="500" height="500"></canvas>
<script src="./js/util.js"></script> 
<script src="./js/bird.js"></script> 
<script src="./js/land.js"></script> 
<script src="./js/pipe.js"></script> 
<script src="./js/sky.js"></script> 
<script src="./js/gameScene.js"></script> 
<script src="./js/overScene.js"></script> 
<script>
        var cvs = document.querySelector( '#cvs' );
        var ctx = cvs.getContext( '2d' );

        util.loadImage({
            bird: './img/bird.png',
            land: './img/land.png',
            pipeDown: './img/pipeDown.png',
            pipeUp: './img/pipeUp.png',
            sky: './img/sky.png'
        }, function( imgObj ) {

            // 根据背景的大小设置画布的大小
            cvs.width = imgObj.sky.width;
            cvs.height = imgObj.sky.height;

            // 游戏场景是否继续
            var isRun = true;

            // 创建游戏场景
            var gameScene = getGameScene( ctx, imgObj );

            // 创建游戏结束场景
            var overScene = getOverScene( ctx );

            // 添加小鸟死亡的听众
            gameScene.addListener( function() {
                isRun = false; // 游戏场景退场
                overScene.draw(); // 结束场景切入
            } );

            // 切入游戏场景，开始游戏
            (function run() {
                gameScene.draw();
                if ( isRun ) {
                    requestAnimationFrame( run );
                }
            }());
        });
    </script>
</body>
</html>